1. Field of the Invention
The present invention relates to a technique of improving the efficiency of the procedure of replacing one or more pages when obtaining a printed matter consisting of a plurality of pages.
2. Description of the Background Art
By virtue of the development of DTP (desk top publishing) technique, digital data described in page description language such as PDF (portable document format) is generally used as a draft manuscript for obtaining a printed matter consisting of a number of pages. Whereas on the side of printing apparatus, so-called digital printing apparatus such as a printer employing electrophotographic process is widely applied, which enables to directly executing printing after a draft digital data is subjected to raster image processing (RIP). Since such a digital printing apparatus does not use any press plate unlike conventional practice, it can provide a multiple-page and small-lot printed matter at a relatively low cost and therefore suitable for the use of on-demand printing.
Printed matter consisting of a plurality of pages often requires a partial revision for the reason, for example, that although there is no need for changing its overall construction and main descriptions, some descriptions disagree with the fact after an elapse of time since the first issue date. For example, in printed matters such as merchandise catalogs issued continuously by a business enterprise and a variety of manuals, the use of which are limited, are usually made by on-demand printing, if the enterprise name is changed or its new factory and the like are established, it is desirable that the name and address of the business enterprise etc. are replaced with the latest content as soon as possible from the standpoint of public confidence, although such a change is irrelevant to the essential contents of the printed matters.
When digital data is used for draft manuscript and a digital printing apparatus executes its printing, data already subjected to RIP and used for printing is usually preserved in reusable condition. Therefore, in the above stated case, all the pages except for one ore more pages to be replaced must be directly used again for printing. It has been however necessary that since the entire draft data configures a single data, even if only one page requires a partial replacement, all the pages including pages irrelevant to the replacement should be subjected again to RIP. This is wasteful and one factor in high cost, for example, from the standpoint of the efficiency of procedure.